[TowerTalk] how to cut exact stubs for band filtering?

[w8ji.tom]

> Hello,
> 
> what is the preferred method to cut EXACT 1/4 or 1/2 wavelength stubs
designed
> for the center of the ssb or cw sections to make transmitting stubs for
> multiop contesting? My equipment park is a poor student's one with the
usual
> meager tools. Could get hold of an oscilloscope but no low C probe head
> available at present. RF1-analyst does not seem to be the right
instrument for
> sharp measurements either. 
> Any other ideas? 

Use a small 12 volt light bulb Con.

Run your rig into a dummy load, through a T connector (or use the W8JI
method of splicing in, it works just as well below two meters). Tap off the
center conductor through the small lamp to the center conductor of the
stub, and tie the shields together. Keep the leads short.

When the bulb is dimmest for the maximum power, the 1/4 wl shorted stub is
resonant.

Light bulbs are more useful than impedance or network analyzers. Impedance
analyzers should be $.25, and light bulbs $25,000. I have all three, and
mostly use the light bulb.

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